The present invention is in the field of melt processing polymers and articles made therefrom; in particular, the present invention is directed to a method of melt processing a stabilized copolymer of vinyl chloride and chlorotrifluoroethylene and an article made from such a composition.
In order to melt process polyvinyl chloride, it is necessary to add plasticizers and stabilizers. Unplasticized polyvinyl chloride is generally described as a rigid compound. In order to melt process polyvinyl chloride, a plasticizer is normally required. Polyvinyl chloride is described as being relatively unstable to heat and light. Stabilizers are typically added to improve the heat and light stability of the polymer. Typical stabilizers include the metallic salts of lead, barrium, tin, or cadmium. Oxides, hydroxides, or fatty acid salts are most effective. Reference is made to F. W. Billmeyer, Jr., Textbook Polymer Science, second edition, John Wiley & Sons, Inc. (1971) at pages 419 through 422.
Copolymers of vinyl chloride, and chlorotrifluoroethylene and processes to form the copolymers are described in a variety of publications and patents. A typical process and publication is Japanese Kokai No. 74 60,391 which discloses copolymers of vinyl chloride and chlorotrifluoroethylene containing from 30 to 80 percent vinyl chloride and 20 to 70 percent chlorotrifluoroethylene. The results of studies of polymers of vinyl chloride and chlorotrifluoroethylene are disclosed in J. Ulbricht and K. Raessler, Synthesis of Copolymers of Vinyl Chloride and Trifluorochloroethylene, Plaste Und Kautschuk 22 (5), 390-393 (1975); and J. Ulbricht, Characterization and Properties of the Copolymers of Vinyl Chloride and Trifluoroethylene, Plaste Und Kautschuk 23 (7), 487 -490 (1976). These references disclose copolymers containing a wide variation of chlorotrifluoroethylene monomer and a copolymer of vinyl chloride and chlorotrifluoroethylene. In the Ulbricht article dated 1976 at page 4 it is noted that the heat stability of the vinyl chloride increases with the amount of chlorotrifluoroethylene incorporated into the copolymer. It is disclosed that the fusibility of the copolymer improves with the addition of chlorotrifluoroethylene.